The way forms works right now is if tasks are received in parallel, the last user to edit a field takes precedent on a fields final value. The way this would not work the way you want is:

1. User 1 opens the form and begins typing in remarks.
2. Before User 1 has submitted User 2 opens the form
3. User 2 types in remarks and submits the form quickly
4. User 1 submits the form after User 2 had already submitted the form
5. User 3 opens the form and sees User 2's remarks, but not User 1's

The way around this is to either 

1. Use the out of the box comments to save remarks as these show the history of comments regardless of submission times
2. Use one remark field per submitter, the way I've done this in the past is to have four columns in a table or 4 unique fields and assign to 4 people at max at a time and show a specific column for each assigned user
   1. Note this cannot be rows, or at least I haven't tested this with the new form designer and field rules, because rows will send empty values and overwrite any value with text in them.
3. Convince the business to do approvals in series so you don't have to worry about setting up and testing parallel approvals